Maxillaria tenuifolia is just like that..gets wrinkly pbs. Usually it is the humidity needs. Our area here is drier, so just the way it is. You can try putting a humidity tray below, it might help. How often do you water it? It likes being moderately moist.
With my plant, it gets wrinkly, but it is a tough plant. How much light is your plant getting. It likes bright light a lot! Much more than Phal light.
New blooms form in between the brown sheaths, and the pbs climb up, you will just be surprised to see something there. If its putting out new growth, then just be patient, the flowers will more or less be coming soon..just watch the brown sheaths from time to time.